Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, a generator, a gearbox, a nacelle, and one or more rotor blades. The rotor blades capture kinetic energy from wind using known airfoil principles and transmit the kinetic energy through rotational energy to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
To properly orient the nacelle and the rotor blades relative to the direction of the wind, wind turbines typically include one or more yaw and/or pitch bearings. Yaw bearings permit rotation of the nacelle and are mounted between the tower and the nacelle. Pitch bearings permit rotation of the rotor blades and are mounted between the rotatable hub and one of the rotor blades. Typically, yaw and/or pitch bearings are slewing ring bearings that include an outer race and an inner race with a plurality of rolling elements (e.g. ball bearings) between the races.
As wind turbines continue to increase in size, the bearings must similarly increase in size due to increased loading. Further, in order for a bearing to withstand such loading, it must include various components that can adequately react to the increased loads. Thus, for example, previous bearings have included spacers between each of the rolling elements to maintain uniform loading throughout the bearing. Such spacers, however, tend to cause ball bunching and/or blade angle asymmetry, which can negatively affect the power necessary to turn the bearing. Thus, overall performance of the wind turbine is negatively impacted. In response, more recent bearings include a cage design constructed of single- or multi-piece elements. However, the individual pieces of the multi-piece cage design tend to overlap each other under high loads, thereby leading to failure of the bearing. In addition, the single-piece cage design is unable to float similar to the multi-piece design, and therefore, can experience wear. Because such bearings can be difficult to access and replace, failure of the bearings can result in a lengthy and expensive repair process.
Accordingly, an improved cage assembly for a bearing of a wind turbine would be welcomed in the technology.